Bore forming sealed coupling and process

ABSTRACT

Opposed ends of two tubular members are relatively displaced toward opposite sides of an annular seal to deform the seal and reduce the seal bore into approximate or actual alignment with the tubular members bore.

BACKGROUND OF THE INVENTION

This invention relates generally to fittings or couplings, and moreparticularly to improvements in effecting seals between the opposed endsof tubular parts or members, with minimum void area for trappingcontaminates next to the through bore of the fitting or coupling.

When tightening tubular parts extending generally coaxially, a seal istypically placed between the tubular parts. Then, when tightening thetube fitting union nuts, the tubular parts load and energize the seal.On some fitting or coupling designs, there is a void space formedbetween the opposed ends of the tubular parts, radially inwardly of theseal, that tends to trap foreign material. This type of design becomesincompatible with the desired smooth bore to be formed by the fittings.Bore interruptions at the seal location can trap fluid which then leadsto later contamination of fluid passed through the fitting.

There is need for an improved fitting or coupling assembly not subjectto such problems and disadvantages.

SUMMARY OF THE INVENTION

It is a major object of the invention to provide a fitting or couplingassembly that will meet the above needs. As will appear, the providedcoupling is characterized as interconnecting two tubular parts betweenwhich a seal is held or compressed by protrusions on the opposed ends ofthe tubular parts. The opposed ends are displaced toward one another tocause the protrusions to penetrate and deform the seal and reduce itsbore into approximate flush relation with the tubular part bores, thuseliminating any appreciable fluid entrapment space.

As will be seen, the two protrusions are desirably alike in shape, andpenetrate the seal to substantially reduce the seal thickness, axially,at the closest separation of the protrusions. The tubular parts and sealare typically metallic.

It is another object of the invention to provide two annular protrusionsas referred to, each such protrusion having a first portion that isconcave in axial radial planes, a second portion that is convex in axialradial planes, and the second portion intersecting the seal bore at alocus which is at an axial distance "d" from a plane tangent to a noseformed by said convex portion, the distance "d" being substantially lessthan the axial overall dimension of the protrusion.

Another object is to provide such smooth bore forming elements incombination with coupling members having shoulders respectively engagingshoulders carried on the tubular parts, to transmit force to the tubularparts for displacing them as referred to. As will be seen, one of theshoulders carried on one of the tubular parts may be defined by a torqueisolator washer received on the one tubular part and blocked againstrotation relative to the coupling member which engages the other of thetubular parts.

Yet another object is to provide a method of sealing off between theopposed annular ends of tubular parts, the coupling member having bores,the steps that include:

a) locating the ends in spaced apart relation, with the tubular partsextending coaxially,

b) providing an annular seal between the opposed ends, the seal having abore that is larger than the tubular part bores,

c) relatively displacing the tubular parts to cause the annular endsthereof to engage opposite sides of the annular seal,

d) and controllably further relatively displacing the tubular parts tocause the annular ends thereof to compressively deform the seal and toreduce the seal bore into approximate flush relation with the tubularpart bores.

These and other objects and advantages of the invention, as well as thedetails of an illustrative embodiment will be more fully understood fromthe following specification and drawings, in which:

DRAWING DESCRIPTION

FIG. 1 is a section taken in elevation through coupling elements inexploded condition prior to make-up;

FIG. 2 is a section like FIG. 1 showing the FIG. 1 coupling in made-upcondition;

FIG. 2a is an enlarged fragmentary section showing seal deformation;

FIG. 3 is an end view of a female coupling taken on lines 3--3 of FIG.1;

FIG. 4 is an end view of a torsion isolator, as employed in FIGS. 1 and2;

FIG. 5 is an end view of a male coupling member, as employed in FIGS. 1and 2;

FIG. 6 is an axial view of a lock element as employed in FIGS. 1 and 2;

FIG. 7 is a section like FIG. 1 showing a modification;

FIG. 8 is a view like FIG. 2 showing the modification of FIG. 7 inmade-up condition; and

FIG. 9 is an enlarged fragmentary view of a protrusion profile taken onlines 9--9 of FIG. 7.

DETAILED DESCRIPTION

In FIGS. 1 and 2, two tubular parts 10 and 11 extend coaxially and haveopposed ends. Flanges 12 and 13 on those parts define such ends at 14and 15, and the flanges include annular protrusions 14a and 15a (eachhalf toroidal) that present convex surfaces engageable with oppositeflat sides of a metallic annular seal or compression washer 16. Couplingstructure is provided to urge the ends 14 and 15 toward one another sothat protrusions 14a and 15a may tightly engage and seal against theannular seal 16 without rotary twisting movement about axis 17.

For this purpose, the tubular parts are provided with shoulders 20 and21 facing axially oppositely away from the seal. Force is applicableagainst those shoulders to urge the parts 10 and 11 toward one another,without relative twisting. To this end, two tubular members are providedto define or extend coaxially with axis 17. See in this regard malemember 23, and female member 24, adapted to coaxially receive therespective tubular parts 10 and 11, and to transmit axial force thereto,via the shoulders 20 and 21, when the members are made up. In thisregard, member 23 has a bore 25 to receive tubular part 10, acounterbore 26 to receive flange 12, and a step shoulder 27 engageablewith shoulder 20 on tubular part 10, to urge that tubular partrightwardly. Member 23 also has an external screw thread at 28 forthreaded interengagement with interior "box" thread at 29 on femalemember 24, as is clear from FIG. 2. Member 24 has a bore 30 closelyreceiving the outer surface of part 11, a thread tip defined "bore" 31to receive the forwardmost structure 42 and 43 of the member 23, and ashoulder 32 facing axially leftwardly to act as a pusher surface.

A torque isolator washer 34 bears against shoulder 21 on tubular part11, and generally longitudinally projecting means 42 and 43 ispositioned or carried on the male member 23 to block rotation of theisolator washer 34 relative to that member 23, and about axis 17. Asseen in FIG. 4, the washer 34 has peripheral flat means engaged by theprojection means to effect the blocking of rotation of the washer 34relative to male member 23. As shown, two parallel flats 40 and 41 areprovided at the rim of the washer 34, at opposite sides of the axis 17;and the projection means preferably comprises two longitudinalprojections 42 and 43 integral with 23, and spaced outwardly relative tocounterbore 26 inasmuch as the flats 40 and 41 are also spaced outwardlyof the counterbore 26 that also closely receives the two flanges 12 and13. The projections 42 and 43 have flats 42a and 43a located close to,i.e, overlapping, the flats 40 and 41, respectively, to be engageabletherewith and block rotation of the washer 34, as seen in FIG. 2. Thatwasher 34 has plate shape, as seen in the drawings Flats 42a and 43aface radially inwardly. The end of the male member 23 from which theprojections 42 and 43 extend is indicated at 46. See also co-pendingU.S. Pat. Application Ser. No. 493,423 to Miller.

Upon make-up of the coupling, the nut member 24 is rotatably threadedonto member 23, while the latter is held against rotation, as by awrench gripping external flats 47 on 23. Flats 24c on 24 may also begripped by a wrench. Such rotation of member 24 brings step shoulder 32(i.e., pusher surface) into forcible engagement with the right face 34aof the torsion isolating washer 34, as seen in FIG. 2. Make-up force isthus transmitted via 34 and shoulder 21 to part 11 for effectingsqueezing of the annular seal 16. Washer 34 acts to isolate thefrictional torsion exerted by the rotating step shoulder 32, and preventtorque transmission to the surface 21, since the projections 42 and 43block rotation of the washer 34 by virtue of the interengageable flatson the projection and isolator annulus. Accordingly, tubular parts 10,11, member 23, and washer 34 all may be considered as non-rotating,relative to member 24 as the latter is rotatably tightened onto member23.

A C-shaped interior clip or ring (spring ring) 54 is also preferablyprovided to grip part 11 at the outer surface 55 of that part, as shown,for positioning the annulus 34 on the part 11, adjacent flange 13. Thenut member 24 has an annular recess 58 intersecting bore 30 and stepshoulder 32 to receive the spring ring upon make-up. The clip or ring 54also initially prevents rotation of the washer 34 to keep the flats 40and 41 on the washer 34 axially aligned with the flats 42a and 43a onthe projections 42 and 43 during make-up.

Note that the terminal ends 42a and 43b of the projections 42 and 43remain spaced from the step shoulder 32 during make-up. Accordingly, thewasher 34 is sufficiently thick to serve a spacing function, keeping theends 42b and 43b spaced from 32.

The elements may consist of the following materials:

10 316 stainless steel

11 316 stainless steel

23 316 stainless steel

24 316 stainless steel

16 nickel

34 316 stainless steel

54 316 stainless steel

In accordance with the invention herein, the annular protrusions 14a and15a are shaped so as to compressively deform the annular seal 16, asbetter seen in FIG. 2a. Note that the protrusions 14a and 15a penetrateopposite sides of the annular seal 16 to cause axial expansion orthickening at annular seal region 16a, axial thinning or reduction atannular seal region 16b, and some lesser thinning or reduction atannular seal region 16c. Thus, the seal becomes radially locked inposition during make-up. Note that initially the annular seal borediameter at 16d in FIG. 1 is greater than the bore diameters 10a and 11aof the tubular parts 10 and 11. The resultant bore diameter of theannular seal 16, after deformation, is substantially flush with the borediameters 10a and 11a of the tubular parts 10 and 11. This minimizes thepossibility of void formation to trap associated fluids, such as gases,which might reduce the ultra clean (i.e., uncontaminated) conditionsdesired in certain fluid flow applications.

In FIGS. 7 and 8, the elements corresponding to those in FIGS. 1 and 2bear the same numerals. The washer 34 is omitted, as are elements 42, 43and 54. The elements referred to above in association with FIG. 2a arepresent, however, and the annular seal 16 is penetrated by theprotrusions 14a and 15a to an extent to again produce a flushness withthe tubular part bores 10a and 11a with the bore of the deformed seal,seen at 163.

FIG. 9 shows that the protrusion, as at 15a, has concavity at 15b,convexity at 15c, and intersects the bore 11a at a rim 15d, which isspaced axially small distance "d" from the plane 15e of the convex noseof the protrusion. These dimensional relationships assure that the borediameter of the deformed seal will be brought into approximately flushrelation with the bores 10a and 11a. The opposite protrusion 14a is thesame as 15a, but mirror imaged relative thereto. The distance "d" issubstantially less than the overall axial dimension "5" of theprotrusion; "d" is typically less than 1/5 "t".

I claim:
 1. In the method of sealing off between the opposed annularends of two tubular parts, said parts having bores, the steps thatinclude:a) locating said ends in spaced apart relation, with saidtubular parts extending coaxially, b) providing an annular seal betweensaid opposed ends, said seal having a bore that is larger than thetubular part bores, c) relatively displacing said tubular parts to causesaid annular ends thereof to engage opposite sides of the annular seal,d) and controllably further relatively displacing said tubular parts tocause said annular ends thereof to compressively deform said seal toreduce the seal bore into approximate flush relation with the tubularpart bores.
 2. The method of claim 1 wherein said opposed annular endsform protrusions extending axially oppositely toward the seal, and saidstep d) includes causing said protrusions to compressively penetratesaid seal.
 3. The method of claim 1 wherein said tubular parts and sealar metallic.
 4. The method of claim 2 including providing tubularrelatively rotatable coupling members having shoulders respectivelyengageable with shoulders carried on said tubular parts, and includingprogressively rotatably interconnecting said coupling members totransmit force to said tubular parts for displacing the tubular parts asper c) and d) of claim
 1. 5. The method of claim 4 including providing atorque isolator washer on one of said tubular parts in spaced relationto said protrusion to transmit said axial force and including blockingrotation of said washer relative to the coupling member engaging theother tubular part during relative rotation of said coupling members. 6.The method of claim 2 including locating said protrusions to effect areduction in the thickness of the annular seal at its bore when thatbore is brought into said flush relation with the tubular part bores. 7.In apparatus for sealing off between the opposed annular ends of twotubular parts, said parts having bores, said apparatus comprising:a)said parts having end protrusions which extend at said ends annularlyand convexly toward one another, b) there being an annular seal betweensaid protrusions, said seal having a bore, c) said parts beingrelatively displaced toward one another so that said protrusionscompressively deform the seal to reduce the seal bore into approximateflush relation with the part bores, d) said protrusions defining a gaptherebetween, said gap having a substantially minimum dimension at thebores defined by said parts.
 8. The combination of claim 7 wherein saidprotrusions are alike in shape, and penetrate the seal to substantiallyreduce the seal thickness, axially, at the closest separation of theprotrusions.
 9. The combination of claim 7 wherein said tubular partsand seal are metallic.
 10. The combination of claim 7 wherein saidtubular parts consist of steel, and said seal consists of nickel ornickel alloy.
 11. The combination of claim 7 including interfittingcoupling members having shoulders respectively engaging shoulderscarried on said tubular parts to transmit force to said tubular partsfor displacing them as per c) of claim
 7. 12. The combination of claim11 wherein one of said shoulders carried on one of said tubular parts isdefined by a torque isolator washer received on said one tubular partand blocked against rotation relative to the mating coupling memberwhich engages the other of said tubular parts.
 13. In apparatus forsealing off between the opposed annular ends of two tubular parts, saidparts having bores, said apparatus comprising:a) said parts having endprotrusions which extend at said ends annularly and convexly toward oneanother, b) there being an annular seal between said protrusions, saidseal having a bore, c) said parts being relatively displaced toward oneanother so that said protrusions compressively deform the seal to reducethe seal bore into approximate flush relation with the part bores, d)each annular protrusion having a first portion that is concave in axialradial planes, a second portion that is convex in axial radial planes,and said second portion intersecting a part bore at a locus which is atan axial distance "d" from a plane tangent to a nose formed by saidconvex portion, said distance "d" being substantially less than theaxial overall dimension of said protrusion.